The list of upcoming guest stars was revealed over the weekend at the show's Comic-Con panel, but the big news was the announcement that the cast of "Family Guy" will be making a trip to Springfield in an upcoming episode, with "Simpsons" cast members Dan Castellaneta, Julie Kavner, Nancy Cartwright and Yeardley Smith all welcoming their new "albino" friends.

This isn't the first such animated crossover -- "Family Guy" creator Seth McFarlane voiced a character last season on "The Simpsons" and Castellaneta did a cameo on an episode of "Family Guy" last season -- but it's the most prominent crossover between the two shows.

"South Park," the other long-running animated series on TV, beat them both to the punch with a two-part story in 2006 that featured the "South Park" boys traveling to the "Family Guy" writers' room, only to discover it's filled with manatees knocking balls with punch lines into baskets. Along the way, they encounter Bart Simpson. None of the actual actors voiced any of the characters that time, however.

However, the "Simpsons"-"Family Guy" episode isn't scheduled to air until fall 2014.